Knife sharpening machine



July 19, 1955 5055 2,713,236

KNIFE SHARPENING MACHINE Filed June 1, 1953 NORM/9N L G 05 5 IN V EN TOR.

BY i s United States Patent KNIFE SHARPENING MACHINE Norman L. 6055, Pasadena, Calif.

Application June 1, 1953, Serial No. 358,609

2 Claims. (Cl. 51-128) This invention relates to a knife sharpening and serrating machine and a method for sharpening and serrating of knives such as steak knives or the like. It has been discovered that in the serrating of knives or the sharpening of serrated knives, it is essential prior to the formation of the serrations on the knife to condition the knife by grinding or otherwise forming a V-shaped lmife edge, the edges of which are beveled to substantially 16. Thereafter, the knife may be presented to a rotating hob and held thereon with a yielding pressure. However, the usual steak knife is provided with a curved end, and the problems arises of how to carry the serrations up and around this curved end.

it is another object of this invention to provide a method which accomplishes this object.

it is another object of this invention to provide a serrating machine incorporating novel methods for guiding the knife and applying the pressure during the bobbing operanon.

It is a feature of this invention that very simple arm and wheel means are used mounting a rotating wheel with a V-shaped rim over a guide slot by means of which by a mere application of finger pressure, an operator may apply the desired pressure to the knife during the hobbing operation.

These and other features, objects and advantages of the present invention will be apparent from the annexed specification in which:

Figure 1 is a side elevation of the device embodying the present invention.

Figure 2 is a fragmentary plan view of the grinding portion of this invention.

Figure 3 is an enlarged section taken along the line 3-3 of Figure 2.

Figure 4 is a section taken along the line 4-4 of Figure 1.

Figure 5 is an enlarged fragmentary section similar to Figure 4 showing the finishing steps in the process.

Referring now more particularly to the drawings, there is shown a base on which there is removably mounted an electromotor 11 by means of bolts 12. The electromotor 11 drives a shaft 13 through a universal joint 14 which in turn drives a shaft 15 carrying a worm 15a mounted in a housing 16, which worm meshes with a gear 17 keyed on a shaft 18 housed in a bearing 19, the other end of which shaft 18 mounts a hob 20. The housing 16 in the upper central portion thereof is provided with a slot 21 directly overlying the center portion of the hob and extending the full length of the upper portion of the housing 16.

A post 22 is carried by the upper side of the housing 16 and pivotally mounts, as by a screw 23, an arm 24. The arm 24 in turn pivotally mounts a wheel 25 having a V-shaped rim 26. The wheel is thus disposed to directly overlie the slot 21. The arm 24 is provided with a verti- 2,713,236 Patented July 19, 1955 cal extension 27 running generally perpendicular to the remainder of the arm 24.

The shaft 15 continues beyond the housing 16 and has keyed thereto a grinding wheel 28 which is disposed between a pair of beveled guide posts 29 and 30, as is conventional in such grinding wheels.

In carrying out the process of this invention, a knife in need of sharpening or serrating is first placed, as shown in Figure 2, in the grinder. The guide posts 29 and 30 have their guide edges disposed at approximately 16 to the grinding wheel. In this manner, a 16 bevel is ground on each edge of the cutting edge of the knife.

The knife is then taken and placed in the slot 21, as shown in Figure and the arm 24 carrying the wheel 25 is pivoted in a counterclockwise direction (Figure 4) until the V-shaped rim of the wheel 25 engages the upper edge of the knife. The operator then applies finger pressure to pull the upper end of the arm 27 towards him, thus applying the desired amount of pressure upon the knife. At this point, the electromotor is energized, and the hob proceeds to cut the serrations in the knife edge, the knife traveling to the left as shown in Figure 4 as the successive serrations are cut by the hob.

When the operator observes the knife approaching the rounded end 31 of the knife, he takes a grip upon the end of the handle of the knife while maintaining pressure on the arm 27, and as the knife presents the rounded end of the knife to the hob, the outer end of the handle is raised and the knife tilted, as shown in Figure 5, to permit the hob to grind the serrations for the full length of the curved edge of the knife.

The knife having thus been sharpened and serrated is likely to be burred on one or more of its edges, and the knife is now re-presented to the grinding wheel 28 to remove the burrs. This having been done, the operation is complete.

While there has been described what is at present considered a preferred embodiment of the present invention, it will be appreciated by those skilled in the art that various changes and modifications can be made therein without departing from the essence of the invention and it is intended to cover herein all such changes and modifications as come within the true spirit and scope of the appended claims.

I claim:

I. A knife sharpener comprising a frame; means defining a vertically disposed slot in said frame; a hob mounted below said slot, power means for driving said hob; a post on said frame; an arm pivotally mounted on said post; and a wheel having a V-shaped rim pivotally mounted on said arm in position to overlie said slot.

2. A knife sharpener comprising a frame; means defining a vertically disposed slot in said frame; a hob mounted below said slot, power means for driving said hob; a post on said frame; an arm pivotally mounted on said post; a wheel having a V-shaped rim pivotally mounted on said arm in position to overlie said slot; and said arm having a generally vertically extending extension thereon substantially perpendicular to the remainder of said arm.

References Cited in the file of this patent UNITED STATES PATENTS 822,070 McLeran May 29, 1906 1,435,514 Burns Nov. 14, 1922 FOREIGN PATENTS 524,763 Great Britain Aug. 14, 1940 

